[Necessity for ECG triggering in digital subtraction angiography. Construction of a simple trigger device]

Movement unsharpness during digital subtraction angiography of the aortic arch and supra-aortic vessels can be avoided by means of ECG gating. The usual techniques resulted in exposures during the phase of least cardiac movement. The relatively long exposure time of about 60 to 300 msec caused marginal blurring during the exposure. An ECG-triggered device is described which produces short exposure times for the mask and filled frame during identical cardiac phases. An example with and without ECG gating shows marked improvement in detail rendering. The design of an ECG-triggered device with digitally adjustable delay and freedom from interference is described.